The author reviews the history of superconductivity. He considers the breakthrough of low temperature superconductors; the progress of high temperature superconductors; the environmental needs of ...superconductivity and finally the assessment and challenges of future superconducting technology.
For over 100 years, scientists have investigated the properties of the proton, which is one of the most abundant components of visible matter in the universe. Nevertheless, researchers do not fully ...understand many details about its internal structure and dynamics. Time-like electromagnetic form factors are one of the observable quantities that can help us achieve a deeper understanding. In this review article, we present an overview of the current experimental status in this field, consisting of measurements of the time-like reactions \(e^{+}e^{-}\to p\bar{p}\), \(p\bar{p}\to e^{+}e^{-}\), and future measurements of \(p\bar{p}\to \mu^{+}\mu^{-}\). A focus is put on recent high precision results of the reaction \(e^{+}e^{-}\to p\bar{p}\) that have been obtained after analyzing 688.5~pb\(^{-1}\) of data taken at the BESIII experiment. They are compared and put into perspective to results from previous measurements in this channel. We discuss the channels \(p\bar{p}\to e^{+}e^{-}\) and \(p\bar{p}\to\mu^{+}\mu^{-}\) in terms of the few existing as well as future measurements, which the PANDA experiment will perform. Finally, we review several new theoretical models and phenomenological approaches inspired by the BESIII high precision results and then discuss their implications for a deeper understanding of the proton's structure and inner dynamics.
To study the nature of the state $Y(2175)$, a dedicated data set of $e^+e^-$
collision data was collected at the center-of-mass energy of 2.125 GeV with the
BESIII detector at the BEPCII collider. By ...analyzing large-angle Bhabha
scattering events, the integrated luminosity of this data set is determined to
be $108.49\pm0.02\pm0.85$ pb$^{-1}$, where the first uncertainty is statistical
and the second one is systematic. In addition, the center-of-mass energy of the
data set is determined with radiative dimuon events to be
$2126.55\pm0.03\pm0.85$ MeV, where the first uncertainty is statistical and the
second one is systematic.
High field superconducting tape magnet technology Rosner, C.H.; Markiewicz, W.D.
IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States),
1992-Jan., 1992-01-00, 19920101, 1992-01-01, Letnik:
28, Številka:
1
Journal Article, Conference Proceeding
Reviews methods of magnet design and materials configuration approaches that were found to be most suitable for high-current-density Nb/sub 3/Sn high-field tape type magnets. Also discussed are ...stability and mechanical and thermal design criteria, with a view towards their applicability to the new, high-temperature superconductor (HTS) materials and high-field magnets. The stability regime of high-temperature superconductors has been analyzed in a manner similar to that previously applied to low-temperature superconductors. The parameters of the conductor which affect stability are temperature dependent, such as the heat capacity; hence, operation at increased temperature can change the stability performance of conductors. The ceramic HTS superconductors may be used in the future at different temperatures depending on the application. In the lower temperature range, the analysis appears to suggest that simple adiabatic stabilization may not suffice for wide tape conductors. Thus, the principles of full penetration stability, utilized heretofore for Nb/sub 3/Sn tape magnets, may be applicable to the stable performance of ceramic superconductors in the intermediate temperature range.< >
Recent applications of one-meter bore Superconducting magnets to allow imaging of human brain tissue, the central nervous system, the spine and other internal organs by utilizing the phenomenon of ...nuclear magnetic resonance (NMR) have resulted in a revolutionary development in medical diagnostics and a unique application of superconductive technology in medicine. At present, S/C magnets are most frequently utilized in MRI systems because they can most effectively produce the highly uniform, stable, and powerful field required for the imaging process. Although it has been demonstrated that quite acceptable image quality can be obtained at virtually any magnetic field strength, from 0.3 Tesla through 2.0 Tesla, the question of optimum central field for MR Imaging and Spectroscopy is still open. Since S/C magnets offer the widest range of field strengths, they are helping to contribute to the collection of clinical data which will eventually clarify the question of optimum central field for Magnetic Resonance diagnostic applications. In addition, S/C magnets have contributed to the successful application of MRI in mobile, or truck-based systems, with operating data on S/C magnets showing high magnet system availability in actual clinical mobile use. This data will be reviewed as will the design considerations of the S/C MRI magnet cryostat and cryogen recondensers, particularly as they relate to reliability, uptime, and system level interactions with the imaging hardware and software.
To study the nature of the state \(Y(2175)\), a dedicated data set of \(e^+e^-\) collision data was collected at the center-of-mass energy of 2.125 GeV with the BESIII detector at the BEPCII ...collider. By analyzing large-angle Bhabha scattering events, the integrated luminosity of this data set is determined to be \(108.49\pm0.02\pm0.85\) pb\(^{-1}\), where the first uncertainty is statistical and the second one is systematic. In addition, the center-of-mass energy of the data set is determined with radiative dimuon events to be \(2126.55\pm0.03\pm0.85\) MeV, where the first uncertainty is statistical and the second one is systematic.
A superconducting magnet system has been designed and constructed; it now operates to a field of 17.5 Tesla. The system consists of an outer Nb 3 Sn solenoid with a 160 mm bore producing 13.5 T, and ...an inner V 3 Ga solenoid with a 31 mm bore producing an incremental 4 T. Electrical transients were monitored in the outer magnet during normal transition and compared with predictions. The inner magnet operates close to the critical current of the V 3 Ga as measured in small coil tests. The magnet system was driven normal several times at a stored energy level of approximately 1.8 Megajoules, activating protective circuitry, designed to safely dissipate the energy released.
A process has been developed for modifying the surface topography of Nb 3 Sn tapes produced by the diffusion process such that losses at 60 Hz and 4.2 K are reduced by a factor of 4 or more. The ...process comprises an etching sequence followed by reapplication of tin; the latter operation restores solderability for the subsequent fabrication of laminated conductor and, under some conditions, contributes to the reduction of ac losses. The treated superconductor tapes apparently fulfill the essential requirements established for superconducting ac power transmission cables.
